In the name of our forgiving and loving God. I have received your telegraphs and letters containing your questions. Now that I have returned safely to the Holy city of Najaf (by the grace of Allah), I will provide you with the answers to your questions regarding the various mourning methods practiced in commemoration ceremonies held in the first 10 days of Muharram and on Ashura for the martyrdom of Imam Husein (may peace be upon him):
Firstly: It is evident that during the first 10 days of Muharram there are widespread displays of crowds and groups who mourn on the streets and public roads, and without a doubt these actions are not only permissible but recommended, and have a manifest aim towards the remembrance of The Master of Martyrs. These practices are the best means to promote the cause of Imam Husein ibn Ali (may peace be upon him) in preserving the holy Qur'an and protecting the true faith, both far and wide. However, these actions must be pure from every prohibited and sinful act such as musical songs, playing musical instruments and dancing, arguing and pushing through the crowd, and fighting. However, even if sinful acts were to take place it would not affect the holiness of the actions performed in commemorating Imam Husein's martyrdom (may peace be upon him). For example it remains like this that if a man was to look at an unlawful woman whilst praying, he has committed a sinful act however his prayer is still in order.
Secondly: It is permissible to hit oneself on the chest or face, even if it causes the body to turn red or black. Likewise, the use of chains (bladed or non-bladed) on the shoulders and back causing the body to turn red or black or even blood to emerge is permissible. With regards to striking oneself with a sword on the head causing blood to emerge, if done without any harm to one's health, it is permissible. Actions that cause blood to emerge from the head should be done so without harming the skull, and normally this is the case, since those who perform this act have the correct skills. If whilst in the state of hitting oneself on the head with a sword, one was sure from past experiences that they would not see any damage, however during this act a lot of blood started to flow, there is no blame on that person and the reward of performing the act has not been reduced. It remains like a person who performs ablution or a purification-washing (ghusl) thinking that using water is not harmful for his body or one who fasts in the holy month of Ramadhan quite sure that fasting will not harm him, but later it transpires that it actually caused harm to his body – he is not to blame and the holiness of these religious actions have not been reduced either. May God protect our dedication towards the right path in this world and the afterlife.
Thirdly: It is permissible to conduct role-plays such as those that have been customary amongst the shi'ite for centuries in which men may dress as women or women dress as men for a short while, in order to mourn and cause others to cry without changing the 'physical' appearance of their body. However, it is prohibited for men to make themselves 'physically' appear as women by changing their bodily appearance and vice versa. One must be careful that they do not perform forbidden acts during religious role-play and even if one was to commit such a sin, the holiness of the religious action has not been undermined, as explained earlier.
Fourthly: The general usage of instruments (such as drums, cymbals and horns) is permissible, if used to make sounds traditionally heard during ceremonies in mourning for Imam Husein (may peace be upon him), like those used widely by Arabs and also in Najaf today.